This invention relates generally to hand held computers and more specifically to hand held computers having a see-through display.
One of the primary goals of modern electronics has been to reduce the size of preexisting components. Computer design is a classic example of this trend. Computers have evolved from the room size behemoths of the past to the widely recognized desk-top models of today. The current trend is to take such personal computers one step further by making them easier to transport and work with. Laptop computers have been around for some time and are quite well-known. Laptops generally have the same processing capabilities as desk-top versions and are also capable of providing similarly high resolution displays. Another example in this evolution has been the advent of the personal digital assistant (PDA). These devices comprise hand held terminals and some sort of graphical interface/display. To date, these devices are substantially less powerful than their desktop and laptop counterparts, but are none the less useful tools for many applications.
While these various devices have proven to be extremely popular and very useful, they do have their limitations. One of the primary drawbacks is the size of the display. In the case of laptop computers the display represents approximately half of the entire shell of the computer. In the case of the PDA, the display is also rather large, comparatively. The PDA devices can be obtained in a variety of keypad/display configurations; however, the displays will always be larger than a de facto industry standard so that the operator can view and perceive a practical amount of information per screen. Finally, while the display in the PDA is usually smaller than the laptop display, it also has a significantly lower resolution making it impractical for many personal computing functions.
To some extent these smaller scale, portable displays represent the current practical limits of display technology. It is possible to produce very small high resolution displays; however, these devices are generally wasted because the human eye cannot comprehend detail on such a small scale. As an example, there are commercially available displays that are approximately 0.6xe2x80x3 by 0.5xe2x80x3, or roughly the size of a dime, and display 1000 lines per inch. Such a display is capable of resolutions comparable to desktop monitors (640xc3x97480, or greater). Yet, when viewed by itself with the naked eye, all that is perceived is a veritable blur. What this means to the computer industry is that while displays can certainly be improved in quality, they really cannot be marketed as significantly smaller stand alone direct view displays.
It would be desirable to have a stand alone, high resolution display on the order of the size of a watch face, as there are many applications where this would be extremely beneficial. For instance, in today""s military, an individual soldier can gain great benefit and realize increased performance by carrying with him a personal computer. However, it simply would not be feasible to expect or require a soldier to carry a bulky laptop in field conditions. The laptop would be cumbersome and would prevent the soldier from simultaneously carrying out other duties as well as hindering his personal ease of movement. A personal computer in the form of a PDA would be more practical than a laptop style computer, however, the PDA would still distract the soldier by taking his concentration away from other critical duties to focus on the personal digital assistant. Furthermore, the display generates a fair amount of light which would often prevent soldiers in the field from being able to use the device without running the risk of being detected. Finally, these displays usually become very difficult to view in outdoor lighting conditions. Therefore, it is clear that current displays are impractical to use in many field conditions and that even though it would be desirable and technologically possible, miniature displays do not solve this problem because of the perceptual limits of human vision.
There are also many other applications where it would be beneficial to simultaneously view a display and certain background information. In general, it is often helpful to have various types of data superimposed onto a real world view. The simplest form of this, conceptually, would be the combination of two separate video images. While creating special effects for a motion picture, actors often perform in front of a blue (or green) screen. Subsequently, the actors performance is combined with a specially created matte, which contains background imagery, to produce a complete composite image. It is often difficult for the actor(s) to perform with no other visual reference and equally challenging for the director to control the scene. Therefore, the intended background is shown on a monitor and a video output from a video camera (which records the same view as the film camera) is displayed on the same monitor. The resultant layered image, though crude, provides the participants with a preview of the final result.
A similar application is the direct combination of electronic data with an operator""s view of his current surroundings. Ideally, the operator would have a variety of data options to chose from and would also have the ability to input data back into the system.
Currently, the only commercially practical system available to accomplish such simultaneous viewing would be the connection of a digital camera to a computer system. The digitized image(s) can then be viewed or manipulated with the computer, alone or in combination with other graphical information being displayed. However, the problem still remains of reducing the overall size of the entire system to make it practical for personal/field use. Further, the image must be viewed on the computer screen as opposed to real time viewing of the actual object. It may be more beneficial for the operator to view the real world and have an image superimposed on that view, as opposed to collecting the images and reproducing them on a computer monitor. That way, the operator can have far better control over their field of view (i.e., they can easily select the images they wish to combine).
There are a limited number of applications where data is superimposed directly into an operator""s field of view. For instance, certain automobile manufacturers project dashboard information onto the windshield so that a driver can view this information without taking his eyes off the road. Of course, this only provides for viewing the data and not working with it. The ability to manipulate the data requires a more sophisticated link between the real world display and the electronic data display.
One similar technology, which can allow for some control of the electronic data is the helmet mounted or head mounted display. Such devices provide a video display in an eye piece mounted to a helmet which is connected to an external computer/video device. The operator""s other eye is left open to view the surroundings. Such a device suffers two major drawbacks. First, the entire system cannot be mounted to the helmet due to the desire to limit the weight placed on the operator""s head. Thus, the helmet must be tethered to additional systems. Second, the operator is subjected to viewing a different image with each eye. This could result in a loss of depth perception and also prevents the operator from selectively focusing on either image.
Other helmet mounted displays solve some of these problems by allowing the operator to still use both eyes to view his surroundings. Optical information from a computer/video source is projected onto a partially reflective surface which is positioned in the operator""s field of view. The optical data is then reflected directly into the operator""s eye. The operator can shift his focus to either detect the data or to focus on his surroundings. Furthermore, since the reflecting surface is only partially reflective, the operator can view directly through it and therefore no portion of his field of view is entirely obscured. This device is also limited in that only the display can be mounted into the helmet and the operator is essentially tethered to a large amount of processing equipment.
Generally, the head mounted displays have been most often used in military applications. The operator is usually a pilot or a tank commander and the display is connected to the on-board computer and navigational equipment. Similar displays could be tethered to more portable computing systems, such as a body worn computer. Alternatively, the display for a body worn computer could be a hand held component. In either case, problems with mobility and a hindrance of the performance of other duties would still occur. When the display is head worn, the device is always in the users field of view and the physical components are always kept in the same location. In addition people generally feel uncomfortable having components attached to their head, especially when coordinated physical activity is required.
It would be more beneficial to be able to selectively view and subsequently store the display, rather than always having to work around it. That feature could be obtained with a hand held tethered display, however, such a display would suffer from the same drawbacks as the laptop and PDA displays discussed above, i.e., in order to be viewable, they must be larger than is practical to carry in field conditions. With either the head mounted display or the tethered hand held display, some sort of control unit must be provided if the operator is going to be able to manipulate the system, which would certainly be desirable and in some applications is required. A completely separate control would have to be added for the head mounded display. The control unit could be added to the hand held display and would simply increase the overall size of the hand held unit. Neither alternative is desirable. Finally, having a unit strapped to one part of an operator""s body and tethered to another presents a problem for field use in that the component will often become entangled when moving in a restricted environment.
Therefore, there exists a need to provide a personal computing device having a small but high resolution display which allows the user to simultaneously view the display and his surroundings, while providing for compact use and ease of storage.
The present invention is a hand held computer having a see through display which allows an operator to look through the device and view his immediate surroundings and simultaneously view a display from an internal computer. The simultaneous view being made possible by having the two views superimposed.
An optical system has an objective lens which gathers light and directs it into a housing. The image passes through a pentaprism where it is inverted, and subsequently directed through an eyepiece lens where it is viewed by the operator.
A fully functioning computer is mounted in the same housing as the optical system. The computer has a video driver which is connected to a miniature display. External controls are mounted on the housing which control the operation of the computer. A color shutter is located adjacent the display in order to produce a color image from the miniature display.
An image combination system takes the color image created by the display and shutter and merges that image with the image produced by the optical system. The merged image is then directed into the pentaprism and what is ultimately viewed by the operator is a combination of the two images superimposed on one another.